I use light pollution data that has been around for awhile but most of it has never been combined with Google Maps before. All the maps on this site are full screen, searchable, and the overlay can be toggled on and off. There is a 15 color light pollution map of the United States from Dave Lorenz that some may find more useful than the 8 color.

Besides the US, light pollution data is now easily viewable for almost any place in the world. The data from the Light Pollution Science and Technology Institute has been available for years but I'm not aware of any other websites that made it all easily viewable.

Also on the site I included some links and information about how to reduce light pollution. I'm planning to have a section that will have an extensive list of observing sites. But that will remain under construction for awhile longer as I try to find a way to integrate some useful features.

Please let me know how you like the website and if you have any suggestions to make it better.

I like it. Nice job Kevin! Not quite sure what to make of the variance in colour from the google overlay as 3 of the 4 sites I might normally visit show as darker in your version. Talking about Ontario,Canada about 300 miles north of Toronto, 150 miles East of Toronto and the north shore of lake Erie.

I like it. Nice job Kevin! Not quite sure what to make of the variance in colour from the google overlay as 3 of the 4 sites I might normally visit show as darker in your version. Talking about Ontario,Canada about 300 miles north of Toronto, 150 miles East of Toronto and the north shore of lake Erie.

Eric

Glad you like it. If you are looking at the 2001 map that one subtracts the effects of snow cover. Snow reflects light and shows as an increase in light pollution on the 1996/1997 map.

Thanks! Used it to find two NY State Parks about an hour away that are both close to the dark end of the scale. I've visited both before during the daytime, and they have good open areas for observing, so I plan on going to both on a future dark night.

The original "World Atlas" map ranges are ratios between the artificial sky brightness and an average reference natural sky brightness (corresponding approximately to 21.6V mag/arcsec, although the authors go to pains to point out that the natural sky brightness varies considerably based on several factors, and this scale is best seen as a relative scale).

I'm wondering, based on the many discussions of sky brightness v. extended object contrast, if this is the most helpful way to segment the light pollution ranges? We need not be limited to the same factor of 3x nor the same number of levels.

In fact, it might be good to intentionally use a number of levels that clearly distinguishes this from the Bortle scale, to prevent further confusion.

In fact, it might be good to intentionally use a number of levels that clearly distinguishes this from the Bortle scale, to prevent further confusion.

Attempting to mimic the Bortle scale would simply increase confusion. The color zones based on satellite measurements and the Bortle scale are fundamentally different; there's no way that they can ever correlate with each other.

I deeply regret the original publication of the correlation by the North Virginia Astronomy Club, although their intentions were entirely legitimate. And its propagation through Wikipedia is even more unfortunate. However, the cat's out of the bag now; the harm cannot be undone.

Aside from problems with the underlying data and the fact that it's now more than a decade old, the color zones can at best represent either average skyglow or possibly skyglow under ideal conditions. They don't change from night to night; that's both a good and a bad point.

The Bortle scale represents a subjective evaluation of the sky at one particular time. Despite attempts to smooth it out by using multiple criteria, the assessment is bound to differ from one person to another, and it most certainly varies from one night to another. That's particularly true in the best (lowest) classes. It also inherently factors in transparency as well as artificial skyglow.

SQM measurements are yet another thing. Like the Bortle assessment they vary from night to night -- often by a fair amount. But unlike the Bortle classes they don't take transparency into account. And the SQM measurements are inherently inaccurate at the dark end of the scale due to "contamination" by the Milky Way and zodiacal light.

I use the color zones for two different purposes: to communicate sky conditions between people at different locations and to figure out where to travel to find relatively dark locations. For the former purpose, the current number of levels is probably about right. Any more would give a false sense of precision. For the latter purpose, the more the better.

I tried to avoid defining exactly what the color zones mean, since I know there has been some confusion with the Bortle scale. The color maps are really just a starting point anyway. They don't take into effect elevation, clouds on the horizon reflecting more light, or distant light domes. The only way to see how dark a site truly is, is to visit there on a good night.

I deeply regret the original publication of the correlation by the North Virginia Astronomy Club, although their intentions were entirely legitimate. And its propagation through Wikipedia is even more unfortunate. However, the cat's out of the bag now; the harm cannot be undone.